ABSTRACT
Abstract A b a s i c experimental i n v e s t i g a t i o n was c a r r i e d out i n order t o o b t a i n an e f f e c t i v e and r a t i o n a l method i n p r e d i c t i o n of c o n c r e t e q u a l i t i e s a t very e a r l y age . This paper d e s c r i b e s t h e a n a l y t i c a l r e s u l t s of t h e p h y s i c a l p r o p e r t i e s o f cement p a s t e , mortar and c o n c r e t e a t e a r l y a g e . The r h e o l o g i c a l p r o p e r t i e s o f e a r l y age c o n c r e t e were exper imenta l l y measured by u s i n g a u l t r a s o n i c p u l s e method T
Longitudinal and t r a n s v e r s e wave v e l o c i t i e s o f c o n c r e t e were measured a t t h e same t ime t o o b t a i n t h e r a t i o of a t r a n s v e r s e v e l o c i t y t o a l o n g i t u d i n a l v e l o c i t y through c o n c r e t e which depended on P o i s s o n ' s r a t i o a t each a g e s . This r a t i o changed w i t h e l a p s e d t ime and r e l a t e d t g t h e process o f the s e t o f cement p a s t e . Dynamic bulk modulus K and dynamic shear modulus G were i n c r e a s e d w i t h a g e s , l i k e a r e l a t i o n s h i p between s t r e n g t h and a g e s . There are remarkable d i f f e r e n c e s on r e l a t i o n between measured r h e o l o g i c a l p r o p e r t i e s and mix proport ion , e s p e c i a l l y water cement^ratio and volume of aggrega te . The curve of r a t e o f dynamic modulus dK / d t , dG / d t and r a t e o f frequency d f / d t , where f i s a frequency of t h e f i r s t r e c e i v e d wave, were agreed wi th a curve of t h e heat g e n e r a t i o n speed of cement hydrat ion .
